There's only one character, as far as we know, who actually was in the prequels and hasn't had their memory wiped. Something might be mentioned if it has bearing on what our heroes have to deal with now, but only in the same way we would talk about a historical event that happened over fifty years ago.

There's no need to mention midichlorians out loud. We know what Jedis are and what they can do, and the Force doesn't need technobabble explanations to slow down the plot. Luke probably has trained an entire new generation by now, and they're doing the recruitment and training offscreen somewhere.

A hologram or portrait of Padme seen in Leia's residence is more than enough.